With the continuing expansion in air travel brought on by the global marketplace, the aviation industry stands to gain an even greater share of the world's markets, and continued competitiveness is important to airplane operators as the aviation industry grows. Quieter airplanes have a competitive advantage, and aircraft noise continues to be a barrier to growth in the aviation industry. Increases in air traffic and growth in populations that surround airports result in a noise impact on a larger percentage of the community and a stronger desire to reduce the noise around airports. For example, concerns about aircraft noise have resulted in noise based landing fees at some major airports. Accordingly, aircraft manufacturers desire technologies across their product line to further reduce noise.
During airport approach and landing, airframe noise is the dominant noise source. The noise that is generated at the side edges of the flaps, elevons, and slats has been identified as an important airframe noise component and is a target for noise control. Previous noise reduction efforts related to side edge noise reduction have been complex and difficult to implement on actual aircraft which may counter any noise reduction value from previous reduction efforts.